What is the ruling on blood that comes down due to the birth control injection and continues for more than twenty days? Is it menstrual blood that necessitates abandoning prayer and fasting, or is it istiḥāḍah (non-menstrual vaginal bleeding)?

If the injection causes significant medical harm, such as bleeding and menstrual cycle disturbances that affect the rulings of purity (tahara) and prayer (salat), then it is not permissible to resort to it for contraception unless there is a verifiable necessity that cannot be removed except by it. This applies, for example, to one who cannot deliver a normal birth or who experiences unbearable hardship due to pregnancy, and no other contraceptive method has been effective for her. It should be noted that coitus interruptus ('azl) and regulating sexual intercourse are safer methods.